Imaging lens

ABSTRACT

A compact imaging lens which meets the demands for low-profileness and a wide field of view and corrects various aberrations properly. The imaging lens includes, in order from an object side to an image side: an aperture stop; a first lens with positive refractive power having a convex surface on the object side; a second lens with negative refractive power as a meniscus lens having a concave surface on the image side; a third lens having a concave surface on the image side; a fourth lens; a fifth lens with positive refractive power having a convex surface on the image side; and a sixth lens with negative refractive power having a concave surface on each of the object side and the image side.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an imaging lens which forms an image ofan object on a solid-state image sensor such as a CCD sensor or C-MOSsensor used in a compact image pickup device, and more particularly toan imaging lens which is built in an image pickup device mounted in anincreasingly compact and low-profile smartphone, mobile phone, PDA(Personal Digital Assistant), game console, information terminal such asa PC or robot, home appliance or vehicle with a camera function.

Description of the Related Art

In recent years, there has been a general tendency that many informationterminals have a camera function. Also, various products with highconvenience such as home appliances with a camera have been introducedinto the market. The demand for home appliances and informationterminals which have a camera function is expected to grow and effortsto develop such products will be accelerated.

The imaging lenses mounted in such products are strongly anticipated notonly to provide high resolution to cope with an increase in the numberof pixels but also to be compact and low-profile enough to match thetrend toward a more compact and low-profile product and offer highbrightness and a wide field of view.

One approach to meeting this demand may be to increase the number ofconstituent lenses from five to six, in order to obtain a higherresolution, since an imaging lens composed of six constituent lenses ishigher in design freedom and more advantageous in correction of variousaberrations than an imaging lens composed of five constituent lenses.

However, when the imaging lens is composed of six constituent lenses,the larger number of constituent lenses may lead to a longer total tracklength. Also, in order to provide an imaging lens which meets all thedemands for low-profileness, a wide field of view and a low F-value, theproblem of difficulty in correction of aberrations in the peripheralarea of an image must be addressed. Unless the problem is addressed, itis difficult to deliver high optical performance throughout the image.

In the conventional art, for example, the imaging lenses described inPatent Literature 1 (JP-A-2012-155223) and Patent Literature 2 (US2012/0243108) are known as imaging lenses composed of six constituentlenses.

Patent Literature 1 discloses an imaging lens which includes, in orderfrom an object side, a first lens group with positive refractive power,a second lens group with negative refractive power, a third lens groupwith positive refractive power, a fourth lens group with negativerefractive power, a fifth lens group with positive refractive power, anda sixth lens group with negative refractive power.

Patent Literature 2 discloses an imaging lens which includes, in orderfrom an object side, a first lens with positive refractive power havinga convex surface on the object side, a second lens, a third lens, afourth lens having at least one aspheric surface, a fifth lens having aconvex surface on the object side and a concave surface on an imageside, and a sixth biconcave lens having at least one aspheric surface.

SUMMARY OF THE INVENTION

The imaging lens described in Patent Literature 1 provides highbrightness with an F-value of about 2.0 to 2.4, and ensures high opticalperformance. However, its total track length is about 8 mm and its fieldof view is about 66 to 70 degrees, which implies that the demands forlow-profileness and a wide field of view cannot be met sufficiently. Ifthe imaging lens described in Patent Literature 1 is adopted to achievelow-profileness and a wide field of view, it is very difficult tocorrect aberrations in the peripheral area and deliver high opticalperformance.

The imaging lens described in Patent Literature 2 is a relativelylow-profile lens which has a total track length of about 5 to 6 mm and aratio of total track length to the diagonal length of the effectiveimaging plane of the image sensor (hereinafter referred to as“TTL-to-diagonal ratio”) of about 1.0 and corrects various aberrationsproperly. However, its field of view is about 70 degrees and its F-valueis about 2.6 to 3.0, suggesting that the brightness is not sufficient tocope with a compact high-pixel image sensor. The imaging lens in Example5 provides high brightness with an F-value of 2.4 but its field of viewof 67 degrees is not sufficient to meet the demand for a wide field ofview. In order for the imaging lens described in Patent Literature 2 toachieve low-profileness, a wide field of view and high brightness, againthe problem with difficulty in correction of aberrations in theperipheral area of an image must be solved.

The present invention has been made in view of the above problem, and anobject of the present invention is to provide a compact high-resolutionimaging lens composed of six constituent lenses which satisfies thedemand for low-profileness, meets the demands for a low F-value and awide field of view in a balanced manner and corrects various aberrationsproperly.

Here, “low-profile” means that total track length is less than 5 mm, theTTL-to-diagonal ratio is about 0.7; “low F-value” means brightness withan F-value of 2.3 or less; and “wide field of view” means a field ofview of about 80 degrees or more. Here, regarding the TTL-to-diagonalratio, the diagonal length of the effective imaging plane of the imagesensor is equal to the diameter of an effective image circle which istwice the maximum image height, in which the maximum image height is thevertical height from an optical axis to the point where a light rayincident on the imaging lens at a maximum field of view enters theimaging plane.

Regarding the terminology used here, a convex or concave surface of alens is defined as a lens surface whose paraxial portion (portion nearthe optical axis) is convex or concave, and a pole point is defined asan off-axial point on an aspheric surface at which a tangential planeintersects the optical axis perpendicularly. Total track length isdefined as the distance on the optical axis from the object-side surfaceof the optical element nearest to the object to the image plane, whenthe thickness of an optical element not involved in convergence ordivergence of light, such as an IR cut filter or cover glass, isair-converted.

According to an aspect of the present invention, there is provided animaging lens to form an image of an object on a solid-state imagesensor, which includes, in order from an object side to an image side: afirst lens with positive refractive power having a convex surface on theobject side; a second lens with negative refractive power as a meniscuslens having a concave surface on the image side; a third lens having aconcave surface on the image side; a fourth lens; a fifth lens withpositive refractive power having a convex surface on the image side; anda sixth lens with negative refractive power having a concave surface oneach of the object side and image side.

The imaging lens according to the present invention includes, in orderfrom the object side, a lens group with positive composite refractivepower including the first lens, the second lens, and the third lens anda lens group with negative composite refractive power including thefourth lens, the fifth lens, and the sixth lens, making a so-calledtelephoto arrangement.

In the above configuration, the positive lens group including the first,second, and third lenses enables the imaging lens to be low-profile andoffer a wide field of view and correct various aberrations properly. Thefirst lens is a lens with positive refractive power having a convexsurface on the object side which has strong positive refractive power toachieve the low-profileness of the imaging lens and a wide field ofview. The second lens is a meniscus lens with negative refractive powerhaving a concave surface on the image side, which properly correctsspherical aberrations and chromatic aberrations which occur on the firstlens. The third lens has a concave surface on the image side andcorrects axial chromatic aberrations, high-order spherical aberrationsand coma aberrations, and field curvature.

The negative lens group including the fourth, fifth, and sixth lensescontributes to the low-profileness of the imaging lens and a wide fieldof view and properly corrects various aberrations. The fourth lenscorrects axial chromatic aberrations, high-order spherical aberrationsand coma aberrations, and field curvature. The fifth lens has a convexsurface on the image side and has strong positive refractive power andits strong positive refractive power is appropriately balanced with therefractive power of the first lens so that the imaging lens islow-profile, offers a wide field of view and properly correctsastigmatism and field curvature. The sixth lens is a lens with negativerefractive power having a concave surface on each of the object side andimage side, which properly corrects spherical aberrations which occur onthe fifth lens and corrects field curvature.

Preferably, in the imaging lens according to the present invention, anaperture stop is located on the object side of the first lens.

When the aperture stop is located on the object side of the first lens,the entrance pupil is remote from the image plane, thereby making iteasy to control telecentricity.

Preferably, the imaging lens according to the present inventionsatisfies a conditional expression (1) below:

0.18<AG16/Σd<0.3  (1)

where AG16 denotes the sum of air gaps on the optical axis between thefirst lens and the sixth lens, and Σd denotes the distance on theoptical axis from the object-side surface of the first lens to theimage-side surface of the sixth lens.

The conditional expression (1) defines an appropriate range for theratio of the sum of air gaps on the optical axis between the first lensand the sixth lens to the distance on the optical axis from theobject-side surface of the first lens to the image-side surface of thesixth lens, and indicates a condition to achieve a short total tracklength. If the value is above the upper limit of the conditionalexpression (1), the ratio of air gaps in the imaging lens system wouldbe too large to shorten the total track length. On the other hand, ifthe value is below the lower limit of the conditional expression (1),undesirably the air gaps between constituent lenses would be too narrow,increasing the risk that the constituent lenses may touch each otherduring the assembling process.

Preferably, the imaging lens according to the present inventionsatisfies a conditional expression (2) below:

20<vd3−vd4<40  (2)

where vd3 denotes the Abbe number of the third lens at d-ray, and vd4denotes the Abbe number of the fourth lens at d-ray.

The conditional expression (2) defines an appropriate range for thedifference in Abbe number at d-ray between the third lens and the fourthlens, and indicates a condition to correct chromatic aberrationsproperly. When a material which satisfies the conditional expression (2)is adopted, chromatic aberrations are corrected properly.

Preferably, in the imaging lens according to the present invention, thefifth lens has an aspheric surface with a pole point off the opticalaxis on the object-side surface.

Since the fifth lens has an aspheric surface with a pole point off theoptical axis on the object-side surface, field curvature and distortionare corrected more effectively.

Preferably, the imaging lens according to the present inventionsatisfies a conditional expression (3) below:

0.2<Ph51/ih<0.9  (3)

where Ph51 denotes the vertical height of the pole point on theobject-side surface of the fifth lens from the optical axis, and ihdenotes maximum image height.

The conditional expression (3) defines an appropriate range for theratio of the vertical height of the pole point on the object-sidesurface of the fifth lens from the optical axis to maximum image height(image size). When the conditional expression (3) is satisfied,off-axial astigmatism and field curvature which increase as the imaginglens is more low-profile and offers a wider field of view are correctedproperly.

Preferably, the imaging lens according to the present inventionsatisfies a conditional expression (4) below:

(f5+|f6|)/f<1.3  (4)

where f denotes the focal length of the overall optical system of theimaging lens, f5 denotes the focal length of the fifth lens, and f6denotes the focal length of the sixth lens.

The conditional expression (4) defines an appropriate range for theratio of the sum of the focal length of the fifth lens and the focallength of the sixth lens to the focal length of the overall opticalsystem of the imaging lens. When the conditional expression (4) issatisfied, the total track length is shortened more appropriately.

Preferably, the imaging lens according to the present inventionsatisfies a conditional expression (5) below:

0.5<f1/f<1.5  (5)

where f denotes the focal length of the overall optical system of theimaging lens, and f1 denotes the focal length of the first lens.

The conditional expression (5) defines an appropriate range for theratio of the focal length of the first lens to the focal length of theoverall optical system of the imaging lens, and indicates a condition tosuppress spherical aberrations and achieve low-profileness and a widefield of view. If the value is above the upper limit of the conditionalexpression (5), the positive refractive power of the first lens would betoo weak to achieve the low-profileness of the imaging lens and a widefield of view, though it is advantageous in suppressing sphericalaberrations. On the other hand, if the value is below the lower limit ofthe conditional expression (5), the positive refractive power of thefirst lens would be too strong and increase spherical aberrations,though it is advantageous in achieving the low-profileness of theimaging lens and a wide field of view.

Preferably, the imaging lens according to the present inventionsatisfies a conditional expression (6) below:

1.5<(r3+r4)/(r3−r4)<4.5  (6)

where r3 denotes the curvature radius of the object-side surface of thesecond lens, and r4 denotes the curvature radius of the image-sidesurface of the second lens.

The conditional expression (6) defines the paraxial shape of the secondlens, and indicates a condition to correct various aberrations properly.When the refractive power of the image-side surface of the second lensis increased within the range defined by the conditional expression (6),chromatic aberrations which occur on the first lens are corrected, andcoma aberrations, field curvature and astigmatism are also correctedproperly.

Preferably, in the imaging lens according to the present invention, thethird lens has positive refractive power, and the fourth lens has aconcave surface on the object side and has negative refractive power.

The third lens having positive refractive power contributes to thelow-profileness of the imaging lens and corrects axial chromaticaberrations, high-order spherical aberrations and coma aberrations, andfield curvature. Also, the fourth lens is a lens with negativerefractive power having a concave surface on the object side, whichsuppresses the angle of light rays incident on that surface and properlysuppresses coma aberrations and high-order spherical aberrations whichoccur on the third lens.

Preferably, in the imaging lens according to the present invention, thesecond lens, the fourth lens, and the sixth lens satisfy a conditionalexpression (7) below:

P4<P2<P6  (7)

where P2 denotes the refractive power of the second lens, P4 denotes therefractive power of the fourth lens, and P6 denotes the refractive powerof the sixth lens and the refractive power of each lens is defined asthe reciprocal of the focal length of each lens.

The conditional expression (7) defines the relation in the magnitude ofrefractive power among the second, fourth, and sixth lenses which havenegative refractive power. The fourth lens, which is located near thecenter of the imaging lens and has the weakest refractive power, mainlycorrects chromatic aberrations, high-order spherical aberrations andcoma aberrations, and field curvature. The second lens, which is locatednear the object and has stronger refractive power than the fourth lens,corrects spherical aberrations and chromatic aberrations which occur onthe first lens. The sixth lens, which is located nearest to the imageplane and has the strongest refractive power, corrects sphericalaberrations and field curvature. When the conditional expression (7) issatisfied, the total track length is shortened and aberrations arecorrected properly.

Preferably, in the imaging lens according to the present invention, thefirst lens, the third lens, and the fifth lens have positive refractivepower and satisfy a conditional expression (8) below:

P3<P1<P5  (8)

where P1 denotes the refractive power of the first lens, P3 denotes therefractive power of the third lens and P5 denotes the refractive powerof the fifth lens, and the refractive power of each lens is defined asthe reciprocal of the focal length of each lens.

The conditional expression (8) defines the relation in the magnitude ofrefractive power among the first, third, and fifth lenses which havepositive refractive power. The third lens, which is located near thecenter of the imaging lens and has the weakest refractive power, mainlycorrects chromatic aberrations, high-order spherical aberrations andcoma aberrations, and field curvature. The first lens, which is locatednear the object and has stronger refractive power than the third lens,suppresses spherical aberrations and contributes to the low-profilenessof the imaging lens and a wide field of view. By appropriately balancingpositive refractive power between the fifth lens and the first lens, thefifth lens, which is located near the image plane and has the strongestrefractive power, contributes to the low-profileness of the imaging lensand a wide field of view and corrects astigmatism and field curvature.When the conditional expression (8) is satisfied, the low-profileness ofthe imaging lens and a wide field of view are achieved and variousaberrations are corrected properly.

When the conditional expression (7) and conditional expression (8) areboth satisfied, correction of aberrations and shortening of the totaltrack length can be achieved appropriately.

Preferably, in the imaging lens according to the present invention, thesixth lens has an aspheric surface with a pole point off the opticalaxis on the image-side surface.

When the sixth lens has a pole point off the optical axis on theimage-side surface, correction of field curvature and distortion andcontrol of the angle of a chief ray incident on the image sensor areperformed more effectively.

Preferably, the imaging lens according to the present inventionsatisfies a conditional expression (9) below:

20<vd1−vd2<40  (9)

where vd1 denotes the Abbe number of the first lens at d-ray and vd2denotes the Abbe number of the second lens at d-ray.

The conditional expression (9) defines an appropriate range for thedifference in Abbe number at d-ray between the first lens and the secondlens, and indicates a condition to correct chromatic aberrationsproperly. When a material which satisfies the conditional expression (9)is adopted, chromatic aberrations are corrected properly.

Preferably, the imaging lens according to the present inventionsatisfies conditional expressions (10) and (11) below:

50<vd5<70  (10)

50<vd6<70  (11)

where vd5 denotes the Abbe number of the fifth lens at d-ray and vd6denotes the Abbe number of the sixth lens at d-ray.

The conditional expression (10) defines an appropriate range for theAbbe number of the fifth lens at d-ray. When a low-dispersion materialwhich satisfies the conditional expression (10) is adopted for the fifthlens which has positive refractive power, chromatic aberrations arecorrected properly. The conditional expression (11) defines anappropriate range for the Abbe number of the sixth lens at d-ray. If thevalue is above the upper limit of the conditional expression (11), itwould be difficult to correct axial chromatic aberrations. If the valueis below the lower limit of the conditional expression (11), it would beeasier to correct axial chromatic aberrations but it would be difficultto correct off-axial chromatic aberrations. When a material whichsatisfies the conditional expression (11) is adopted for the sixth lens,axial and off-axial chromatic aberrations are corrected in a balancedmanner.

Preferably, the imaging lens according to the present inventionsatisfies a conditional expression (12) below:

0.75<D5/D6<1.50  (12)

where D5 denotes the thickness of the fifth lens on the optical axis andD6 denotes the thickness of the sixth lens on the optical axis.

The conditional expression (12) defines an appropriate range for theratio of the thickness of the fifth lens on the optical axis to that ofthe sixth lens on the optical axis. The fifth lens and the sixth lens,both located near the image plane, each have a relatively largeeffective diameter. When their thicknesses are appropriately balancedwithin the range defined by the conditional expression (12), stableformability is ensured.

Preferably, the imaging lens according to the present inventionsatisfies a conditional expression (13) below:

0.35<(T5/f)×100<3.00  (13)

where T5 denotes the distance on the optical axis from the image-sidesurface of the fifth lens to the object-side surface of the sixth lensand f denotes the focal length of the overall optical system of theimaging lens.

The conditional expression (13) defines an appropriate range for thedistance on the optical axis from the image-side surface of the fifthlens to the object-side surface of the sixth lens. If the value is abovethe upper limit of the conditional expression (13), the air gap betweenthe fifth lens and the sixth lens would be too wide to make the imaginglens low-profile and also distortion and field curvature would increase,making it impossible to deliver high optical performance. On the otherhand, if the value is below the lower limit of the conditionalexpression (13), the air gap between the fifth lens and the sixth lenswould be too narrow, increasing the risk that these lenses may toucheach other during the assembling process.

Preferably, the imaging lens according to the present inventionsatisfies a conditional expression (14) below:

0.6<|r7|/f<17.0  (14)

where f denotes the focal length of the overall optical system of theimaging lens and r7 denotes the curvature radius of the object-sidesurface of the fourth lens.

The conditional expression (14) defines an appropriate range for theratio of the curvature radius of the object-side surface of the fourthlens to the focal length of the overall optical system of the imaginglens. If the value is above the upper limit of the conditionalexpression (14), the refractive power of the object-side surface of thefourth lens would be too weak and the angle of off-axial light raysincident on that surface would increase, making it difficult to correctoff-axial spherical aberrations, coma aberrations and field curvature.On the other hand, if the value is below the lower limit of theconditional expression (14), the refractive power of the object-sidesurface of the fourth lens would be too strong and aberrations in theperipheral portion of the lens surface would be corrected excessively,making it difficult to correct high-order spherical aberrations and comaaberrations, and field curvature.

Preferably, the imaging lens according to the present inventionsatisfies a conditional expression (15) below:

0.45<E5/D5<1.20  (15)

where E5 denotes the edge thickness of the fifth lens in the maximumeffective diameter and D5 denotes the thickness of the fifth lens on theoptical axis.

The conditional expression (15) defines an appropriate range for theratio of the edge thickness of the fifth lens in the maximum effectivediameter to the thickness of the fifth lens on the optical axis. Inorder to make a thin small lens by injection molding, from the viewpointof flowability during the molding process, it is desirable that thedifference in thickness between the center and edge of the lens besmall. When the conditional expression (15) is satisfied, the influenceof low flowability on the surface accuracy, sink marks and the like canbe prevented, leading to reduction in the ratio of molding defects andto higher mass productivity.

Preferably, the imaging lens according to the present inventionsatisfies a conditional expression (16) below:

0.6<f12/f<2.0  (16)

where f denotes the focal length of the overall optical system of theimaging lens and f12 denotes the composite focal length of the firstlens and the second lens.

The conditional expression (16) defines an appropriate range for theratio of the composite focal length of the first lens and the secondlens to the focal length of the overall optical system of the imaginglens. If the value is above the upper limit of the conditionalexpression (16), the composite focal length of the first lens and thesecond lens would be too long to shorten the total track length. On theother hand, if the value is below the lower limit of the conditionalexpression (16), the composite focal length of the first lens and thesecond lens would be too short and chromatic aberrations would increase,making it difficult to ensure high optical performance.

Preferably, the imaging lens according to the present inventionsatisfies a conditional expression (17) below:

0.80<ih/f<1.0  (17)

where f denotes the focal length of the overall optical system of theimaging lens and ih denotes maximum image height.

The conditional expression (17) defines an appropriate range for theratio of maximum image height to the focal length of the overall opticalsystem of the imaging lens, which represents the field of view. If thevalue is above the upper limit of the conditional expression (17), thefield of view would be too wide to correct aberrations properly, whichwould make it difficult to correct various aberrations, particularly inthe peripheral area of the image, leading to deterioration in opticalperformance. On the other hand, if the value is below the lower limit ofthe conditional expression (17), it would be easy to correct aberrationsand advantageous in increasing the optical performance but it would bedifficult to achieve a wide field of view.

Preferably, the imaging lens according to the present inventionsatisfies a conditional expression (18) below:

TTL/2ih<1.0  (18)

where TTL denotes total track length and ih denotes maximum imageheight.

The conditional expression (18) defines an appropriate range for theTTL-to-diagonal ratio. If the value is above the upper limit of theconditional expression (18), the total track length would be too long tomeet the demand for low-profileness.

According to the present invention, there is provided a compacthigh-resolution imaging lens which satisfies the demand forlow-profileness, meets the demands for a low F-value and a wide field ofview in a balanced manner and corrects various aberrations properly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing the general configuration of animaging lens in Example 1 according to the present invention;

FIG. 2 shows spherical aberration, astigmatism, and distortion of theimaging lens in Example 1 according to the present invention;

FIG. 3 is a schematic view showing the general configuration of animaging lens in Example 2 according to the present invention;

FIG. 4 shows spherical aberration, astigmatism, and distortion of theimaging lens in Example 2 according to the present invention;

FIG. 5 is a schematic view showing the general configuration of animaging lens in Example 3 according to the present invention;

FIG. 6 shows spherical aberration, astigmatism, and distortion of theimaging lens in Example 3 according to the present invention;

FIG. 7 is a schematic view showing the general configuration of animaging lens in Example 4 according to the present invention;

FIG. 8 shows spherical aberration, astigmatism, and distortion of theimaging lens in Example 4 according to the present invention;

FIG. 9 is a schematic view showing the general configuration of animaging lens in Example 5 according to the present invention;

FIG. 10 shows spherical aberration, astigmatism, and distortion of theimaging lens in Example 5 according to the present invention;

FIG. 11 is a schematic view showing the general configuration of animaging lens in Example 6 according to the present invention;

FIG. 12 shows spherical aberration, astigmatism, and distortion of theimaging lens in Example 6 according to the present invention;

FIG. 13 is a schematic view showing the general configuration of animaging lens in Example 7 according to the present invention;

FIG. 14 shows spherical aberration, astigmatism, and distortion of theimaging lens in Example 7 according to the present invention;

FIG. 15 is a schematic view showing the general configuration of animaging lens in Example 8 according to the present invention;

FIG. 16 shows spherical aberration, astigmatism, and distortion of theimaging lens in Example 8 according to the present invention;

FIG. 17 is a schematic view showing the general configuration of animaging lens in Example 9 according to the present invention;

FIG. 18 shows spherical aberration, astigmatism, and distortion of theimaging lens in Example 9 according to the present invention;

FIG. 19 is a schematic view showing the general configuration of animaging lens in Example 10 according to the present invention;

FIG. 20 shows spherical aberration, astigmatism, and distortion of theimaging lens in Example 10 according to the present invention;

FIG. 21 is a schematic view showing the general configuration of animaging lens in Example 11 according to the present invention;

FIG. 22 shows spherical aberration, astigmatism, and distortion of theimaging lens in Example 11 according to the present invention;

FIG. 23 is a schematic view showing the general configuration of animaging lens in Example 12 according to the present invention;

FIG. 24 shows spherical aberration, astigmatism, and distortion of theimaging lens in Example 12 according to the present invention; and

FIG. 25 is a view of the fifth lens of an imaging lens in an exampleaccording to the present invention, illustrating vertical height Ph51 ofa pole point on the object-side surface from the optical axis, thicknessD5 on the optical axis, and edge thickness E5 in the maximum effectivediameter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the preferred embodiment of the present invention will bedescribed in detail referring to the accompanying drawings.

FIGS. 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, and 23 are schematic viewsshowing the general configurations of the imaging lenses in Examples 1to 12 according to this embodiment, respectively. Since all theseexamples have the same basic lens configuration, the generalconfiguration of an imaging lens according to this embodiment isexplained below mainly referring to the schematic view of Example 1.

As shown in FIG. 1, the imaging lens according to this embodimentincludes, in order from an object side to an image side, a first lens L1with positive refractive power, a second lens L2 with negativerefractive power, a third lens L3 with positive refractive power, afourth lens L4 with negative refractive power, a fifth lens L5 withpositive refractive power, and a sixth lens L6 with negative refractivepower. An aperture stop ST is located in front of the first lens L1 withpositive refractive power.

A filter IR such as an infrared cut filter or cover glass is locatedbetween the sixth lens L6 and an image plane IM. The filter IR isomissible. Since an imaging position in the optical system differsdepending on the thickness of the filter IR, in the present invention anaxial distance is defined as an axial distance in which the thickness ofan optical element not involved in convergence or divergence of light,such as an IR cut filter or cover glass, is air-converted.

The imaging lens, composed of six constituent lenses, includes a lensgroup with positive composite refractive power, including the first lensL1, the second lens L2, and the third lens L3, and a lens group withnegative composite refractive power, including the fourth lens L4, thefifth lens L5, and the sixth lens L6, making a telephoto arrangementwhich is advantageous in shortening the total track length.

In the imaging lens composed of six constituent lenses, the aperturestop ST is located between the apex and end edge of the object-sidesurface of the first lens L1, so that the entrance pupil is remote fromthe image plane IM, making it easy to control telecentricity.

The first lens L1 is a lens with positive refractive power having aconvex surface on the object side. The image-side surface of the firstlens L1 has a concave shape with a larger curvature radius than thecurvature radius of the object-side surface to the extent that therefractive power does not become too low and spherical aberrations donot increase, so that the imaging lens is low-profile and offers a widefield of view. Alternatively, the first lens L1 may have a biconvexshape. In that case, by appropriately distributing the positiverefractive power between the object-side surface and the image-sidesurface, spherical aberrations are suppressed and the positiverefractive power is increased, so that the imaging lens is morelow-profile and offers a wider field of view.

The second lens L2 is a lens with negative refractive power having aconcave surface on the image side, which properly corrects sphericalaberrations and chromatic aberrations which occur on the first lens L1.

The third lens L3 has a meniscus shape with a concave surface on theimage side and has positive refractive power. Among the constituentlenses of the imaging lens, it has weak refractive power and contributesto the low-profileness of the imaging lens and corrects axial chromaticaberrations. The aspheric surfaces on the both sides correct high-orderspherical aberrations, coma aberrations, and field curvature.

The fourth lens L4 is a meniscus lens with negative refractive powerhaving a convex surface on the image side, which corrects axialchromatic aberrations and high-order spherical aberrations and comaaberrations, and field curvature. Alternatively, the fourth lens L4 mayhave a biconcave shape as in Examples 4, 10, and 12. In that case,spherical aberrations and axial chromatic aberrations are corrected moreproperly. Also, the fourth lens

L4 may have a meniscus shape with a convex surface on the object side.In that case, field curvature is corrected more properly. In Examples 5to 8, the fourth lens L4 has a meniscus shape with a convex surface onthe object side.

The fifth lens L5 is a biconvex double-sided aspheric lens with strongpositive refractive power having a convex surface on each of the objectside and image side, contributing to compactness of the imaging lens. Ithas a pole point off an optical axis X on the aspheric object-sidesurface and properly corrects astigmatism and field curvature.Alternatively, the fifth lens L5 may have a meniscus shape with a convexsurface on the image side as in Example 7.

The sixth lens L6 is a biconcave lens with negative refractive powerhaving a concave surface on each of the object side and image side. Ithas an aspheric surface on both sides and the aspheric image-sidesurface has a pole point off the optical axis X. These aspheric surfacescorrect spherical aberrations which occur on the fifth lens L5, correctfield curvature and control the angle of a chief ray incident on theimage sensor within an appropriate range.

When all the constituent lenses of the imaging lens according to thisembodiment are made of plastic material, the manufacturing process iseasier and the imaging lens can be mass-produced at low cost. Bothsurfaces of each lens have appropriate aspheric shapes to correctvarious aberrations more properly.

The lens material is not limited to plastic material. The lensperformance can also be further enhanced by using glass material.Although it is desirable that all the lens surfaces have asphericshapes, a spherical surface which is easy to make may be adopteddepending on the required performance.

When the imaging lens according to this embodiment satisfies conditionalexpressions (1) to (18) below, it brings about advantageous effects:

0.18<AG16/Σd<0.3  (1)

20<vd3−vd4<40  (2)

0.2<Ph51/ih<0.9  (3)

(f5+|f6|)/f<1.3  (4)

0.5<f1/f<1.5  (5)

1.5<(r3+r4)/(r3−r4)<4.5  (6)

P4<P2<P6  (7)

P3<P1<P5  (8)

20<vd1−vd2<40  (9)

50<vd5<70  (10)

50<vd6<70  (11)

0.75<D5/D6<1.50  (12)

0.35<(T5/f)×100<3.00  (13)

0.6<|r7|/f<17.0  (14)

0.45<E5/D5<1.20  (15)

0.6<f12/f<2.0  (16)

0.80<ih/f<1.0  (17)

TTL/2ih<1.0  (18)

where

-   -   AG16: sum of air gaps on the optical axis X from the first lens        L1 to the sixth lens L6    -   Σd: distance on the optical axis X from the object-side surface        of the first lens L1 to the image-side surface of the sixth lens        L6    -   Ph51: vertical height of the pole point on the object-side        surface of the fifth lens L5 from the optical axis    -   ih: maximum image height    -   f: focal length of the overall optical system of the imaging        lens    -   f1: focal length of the first lens L1    -   f5: focal length of the fifth lens L5    -   f6: focal length of the sixth lens L6    -   f12: composite focal length of the first lens L1 and the second        lens L2    -   r3: curvature radius of the object-side surface of the second        lens L2    -   r4: curvature radius of the image-side surface of the second        lens L2    -   P1: refractive power of the first lens L1    -   P2: refractive power of the second lens L2    -   P3: refractive power of the third lens L3    -   P4: refractive power of the fourth lens L4    -   P5: refractive power of the fifth lens L5    -   P6: refractive power of the sixth lens L6    -   vd1: Abbe number of the first lens L1 at d-ray    -   vd2: Abbe number of the second lens L2 at d-ray    -   vd3: Abbe number of the third lens L3 at d-ray    -   vd4: Abbe number of the fourth lens L4 at d-ray    -   vd5: Abbe number of the fifth lens L5 at d-ray    -   vd6: Abbe number of the sixth lens L6 at d-ray    -   D5: thickness of the fifth lens L5 on the optical axis X    -   D6: thickness of the sixth lens L6 on the optical axis X    -   T5: distance on the optical axis X from the image-side surface        of the fifth lens L5 to the object-side surface of the sixth        lens L6    -   r7: curvature radius of the object-side surface of the fourth        lens L4    -   E5: edge thickness of the fifth lens L5 in the maximum effective        diameter    -   TTL: total track length.

When the imaging lens according to this embodiment satisfies conditionalexpressions (1a) to (6a) and (9a) to (18a) below, it brings about moreadvantageous effects:

0.21<AG16/Σd<0.3  (1a)

25<vd3−vd4<40  (2a)

0.2<Ph51/ih<0.7  (3a)

(f5+|f6|)/f<1.22  (4a)

0.6<f1/f<1.2  (5a)

1.9<(r3+r4)/(r3−r4)<3.7  (6a)

25<vd1−vd2<40  (9a)

50<vd5<65  (10a)

50<vd6<65  (11a)

0.75<D5/D6<1.30  (12a)

0.42<(T5/f)×100<3.00  (13a)

1.0<|r7|/f<16.0  (14a)

0.45<E5/D5<1.20  (15a)

0.8<f12/f<1.6  (16a)

0.80<ih/f<0.9  (17a)

TTL/2ih<0.8.  (18a)

The signs in the above conditional expressions have the same meanings asthose in the preceding paragraph.

When the imaging lens according to this embodiment satisfies conditionalexpressions (1b) to (6b) and (9b) to (18b) below, it brings aboutparticularly advantageous effects:

0.24≦AG16/Σd≦0.27  (1b)

25≦vd3−vd4≦38  (2b)

0.23≦Ph51/ih≦0.31  (3b)

(f5+|f6|)/f≦1.19  (4b)

0.70<f1/f≦1.2  (5b)

2.13≦(r3+r4)/(r3−r4)≦3.29  (6b)

25≦vd1−vd2≦38  (9b)

50≦vd5≦60  (10b)

50≦vd6≦60  (11b)

0.86≦D5/D6≦1.12  (12b)

0.47≦(T5/f)×100≦2.66  (13b)

1.18≦|r7|/f≦14.34  (14b)

0.50≦E5/D5≦0.6  (15b)

1.15≦f12/f≦1.38  (16b)

0.80≦ih/f≦0.85  (17b)

TTL/2ih≦0.75.  (18b)

The signs in the above conditional expressions have the same meanings asthose in the paragraph before the preceding paragraph.

In this embodiment, the aspheric shapes of the lens surfaces areexpressed by Equation 1, where Z denotes an axis in the optical axisdirection, H denotes a height perpendicular to the optical axis, kdenotes a conic constant, and A4, A6, A8, A10, A12, A14, and A16 denoteaspheric surface coefficients.

$\begin{matrix}{Z = {\frac{\frac{H^{2}}{R}}{1 + \sqrt{1 - {\left( {k + 1} \right)\; \frac{H^{2}}{R^{2}}}}} + {A_{4}H^{4}} + {A_{6}H^{6}} + {A_{8}H^{8}} + {A_{10}H^{10}} + {A_{12}H^{12}} + {A_{14}H^{14}} + {A_{16}H^{16}}}} & {{Equation}\mspace{14mu} 1}\end{matrix}$

Next, examples of the imaging lens according to this embodiment will beexplained. In each example, f denotes the focal length of the overalloptical system of the imaging lens, Fno denotes an F-number, ω denotes ahalf field of view, and ih denotes maximum image height. i denotes asurface number counted from the object side, r denotes a curvatureradius, d denotes the distance on the optical axis between lens surfaces(axial surface distance), Nd denotes a refractive index at d-ray(reference wavelength), and vd denotes an Abbe number at d-ray. As foraspheric surfaces, an asterisk (*) after surface number i indicates thatthe surface concerned is an aspheric surface.

Example 1

The basic lens data of Example 1 is shown below in Table 1.

TABLE 1 Numerical Data Example 1 Unit mm f = 3.86 Fno = 2.24 ω(°) = 38.8ih = 3.14 TTL = 4.43 Surface Data Surface Curvature Surface RefractiveAbbe Number i Radius r Distance d Index Nd Number νd (Object) InfinityInfinity  1 (Stop) Infinity −0.255  2* 1.441 0.555 1.5443 55.86  3*5.904 0.055  4* 5.470 0.223 1.6391 23.25  5* 2.486 0.248  6* 4.087 0.3631.5348 55.66  7* 10.337 0.366  8* −8.933 0.320 1.6391 23.25  9* −165.0690.163 10* 11.888 0.500 1.5348 55.66 11* −1.406 0.050 12* −19.374 0.5501.5348 55.66 13* 1.094 0.300 14 Infinity 0.210 1.5168 64.20 15 Infinity0.599 Image Plane Infinity Constituent Lens Data Lens Start SurfaceFocal Length 1 2 3.35 2 4 −7.34 3 6 12.39 4 8 −14.79 5 10 2.38 6 12−1.92 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5thSurface 6th Surface 7th Surface k 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 A4 −8.069E−03  −3.191E−01  −4.654E−01 −2.766E−01 −2.188E−01  −1.067E−01 A6 4.412E−02 7.599E−01 1.308E+00 8.960E−01 2.427E−01 −6.075E−02 A8 −1.862E−01  −8.703E−01  −1.556E+00 −1.115E+00 −3.744E−01   1.274E−01 A10 2.877E−01 3.098E−01 7.290E−01 7.933E−01 4.795E−01 −1.108E−01 A12 −1.942E−01  0.000E+00 −4.038E−02 −2.012E−01 −1.951E−01   7.600E−02 A14 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 A16 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 8th Surface 9th Surface 10th Surface11th Surface 12th Surface 13th Surface k 0.000E+00 0.000E+00 0.000E+00−1.005E+01 0.000E+00 −7.747E+00 A4 −8.926E−02  −1.969E−01  1.147E−03 9.956E−02 −1.444E−01  −1.173E−01 A6 2.208E−02 2.461E−01 −2.455E−02 −2.506E−02 3.814E−02  6.785E−02 A8 −2.656E−02  −4.107E−01  −2.126E−02 −1.478E−02 2.196E−02 −3.201E−02 A10 −3.513E−02  4.723E−01 7.463E−03−6.263E−03 −1.330E−02   9.913E−03 A12 6.935E−02 −2.971E−01  0.000E+00 1.068E−02 2.524E−03 −1.869E−03 A14 −3.457E−02  9.502E−02 0.000E+00−3.459E−03 −1.657E−04   1.918E−04 A16 0.000E+00 −1.227E−02  0.000E+00 3.508E−04 −2.513E−07  −8.111E−06 f12 = 5.18 E5 = 0.29 Ph51 = 0.79

As shown in Table 13, the imaging lens in Example 1 satisfiesconditional expressions (1) to (18).

FIG. 2 shows spherical aberration (mm), astigmatism (mm), and distortion(%) of the imaging lens in Example 1. The spherical aberration diagramshows the amount of aberration at wavelengths of F-ray (486 nm), d-ray(588 nm), and C-ray (656 nm). The astigmatism diagram shows the amountof aberration at d-ray on sagittal image surface S and the amount ofaberration at d-ray on tangential image surface T (the same is true forFIGS. 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, and 24). As shown in FIG. 2,each aberration is corrected properly.

Example 2

The basic lens data of Example 2 is shown below in Table 2.

TABLE 2 Numerical Data Example 2 Unit mm f = 4.27 Fno = 2.21 ω(°) = 39.0ih = 3.50 TTL = 4.95 Surface Data Surface Curvature Surface RefractiveAbbe Number i Radius r Distance d Index Nd Number νd (Object) InfinityInfinity  1 (Stop) Infinity −0.297  2* 1.629 0.600 1.5443 55.86  3*6.334 0.071  4* 6.327 0.241 1.6503 21.54  5* 3.137 0.283  6* 6.186 0.4571.5348 55.66  7* 25.405 0.381  8* −6.854 0.356 1.6391 23.25  9* −22.0610.182 10* 10.585 0.558 1.5348 55.66 11* −1.537 0.087 12* −11.818 0.5881.5348 55.66 13* 1.222 0.350 14 Infinity 0.210 1.5168 64.20 15 Infinity0.657 Image Plane Infinity Constituent Lens Data Lens Start SurfaceFocal Length 1 2 3.86 2 4 −9.86 3 6 15.16 4 8 −15.70 5 10 2.55 6 12−2.04 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5thSurface 6th Surface 7th Surface k 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 A4 −7.815E−03  −2.319E−01  −3.345E−01 −2.022E−01 −1.591E−01  −8.082E−02 A6 2.576E−02 4.416E−01 7.644E−01 5.221E−01 1.377E−01 −3.405E−02 A8 −8.765E−02  −4.096E−01  −7.303E−01 −5.230E−01 −1.759E−01   6.154E−02 A10 1.083E−01 1.188E−01 2.759E−01 2.994E−01 1.874E−01 −4.191E−02 A12 −5.921E−02  0.000E+00 −1.226E−02 −6.143E−02 −5.946E−02   2.316E−02 A14 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 A16 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 8th Surface 9th Surface 10th Surface11th Surface 12th Surface 13th Surface k 0.000E+00 0.000E+00 0.000E+00−9.875E+00 0.000E+00 −7.946E+00 A4 −6.385E−02  −1.386E−01  2.334E−03 7.014E−02 −1.041E−01  −8.367E−02 A6 1.468E−02 1.447E−01 −1.531E−02 −1.450E−02 2.231E−02  3.971E−02 A8 −9.821E−03  −1.928E−01  −9.872E−03 −6.908E−03 1.032E−02 −1.508E−02 A10 −1.241E−02  1.788E−01 2.639E−03−2.369E−03 −5.034E−03   3.748E−03 A12 2.115E−02 −9.057E−02  0.000E+00 3.256E−03 7.695E−04 −5.700E−04 A14 −8.496E−03  2.335E−02 0.000E+00−8.499E−04 −4.072E−05   4.715E−05 A16 0.000E+00 −2.443E−03  0.000E+00 6.955E−05 −4.526E−08  −1.601E−06 f12 = 5.53 E5 = 0.32 Ph51 = 0.93

As shown in Table 13, the imaging lens in Example 2 satisfiesconditional expressions (1) to (18).

FIG. 4 shows spherical aberration (mm), astigmatism (mm), and distortion(%) of the imaging lens in Example 2. As shown in FIG. 4, eachaberration is corrected properly.

Example 3

The basic lens data of Example 3 is shown below in Table 3.

TABLE 3 Numerical Data Example 3 Unit mm f = 4.27 Fno = 2.20 ω(°) = 39.1ih = 3.50 TTL = 5.00 Surface Data Surface Curvature Surface RefractiveAbbe Number i Radius r Distance d Index Nd Number νd (Object) InfinityInfinity  1 (Stop) Infinity −0.292  2* 1.644 0.597 1.5443 55.86  3*6.665 0.070  4* 5.617 0.240 1.6503 21.54  5* 3.000 0.302  6* 6.642 0.4431.5348 55.66  7* 19.847 0.391  8* −5.479 0.348 1.6391 23.25  9* −24.2170.115 10* 8.727 0.658 1.5348 55.66 11* −1.193 0.020 12* −14.370 0.5861.5348 55.66 13* 0.998 0.350 14 Infinity 0.210 1.5168 64.20 15 Infinity0.739 Image Plane Infinity Constituent Lens Data Lens Start SurfaceFocal Length 1 2 3.85 2 4 −10.27 3 6 18.45 4 8 −11.16 5 10 2.01 6 12−1.72 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5thSurface 6th Surface 7th Surface k 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 A4 −8.188E−03  −2.310E−01  −3.349E−01 −2.019E−01 −1.631E−01  −8.677E−02 A6 2.580E−02 4.417E−01 7.641E−01 5.213E−01 1.347E−01 −3.464E−02 A8 −8.768E−02  −4.102E−01  −7.308E−01 −5.256E−01 −1.761E−01   6.170E−02 A10 1.079E−01 1.185E−01 2.754E−01 3.002E−01 1.891E−01 −4.243E−02 A12 −5.916E−02  0.000E+00 −1.219E−02 −6.153E−02 −5.940E−02   2.314E−02 A14 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 A16 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 8th Surface 9th Surface 10th Surface11th Surface 12th Surface 13th Surface k 0.000E+00 0.000E+00 0.000E+00−7.972E+00 0.000E+00 −7.737E+00 A4 −5.250E−02  −1.437E−01  −3.447E−03  7.333E−02 −1.014E−01  −8.458E−02 A6 1.319E−02 1.465E−01 −1.445E−02 −1.335E−02 2.206E−02  3.993E−02 A8 −1.139E−02  −1.926E−01  −8.533E−03 −6.953E−03 1.029E−02 −1.508E−02 A10 −1.164E−02  1.787E−01 2.448E−03−2.396E−03 −5.037E−03   3.747E−03 A12 2.115E−02 −9.059E−02  0.000E+00 3.250E−03 7.691E−04 −5.702E−04 A14 −8.495E−03  2.335E−02 0.000E+00−8.502E−04 −4.070E−05   4.717E−05 A16 0.000E+00 −2.439E−03  0.000E+00 6.994E−05 −1.855E−08  −1.601E−06 f12 = 5.40 E5 = 0.35 Ph51 = 0.95

As shown in Table 13, the imaging lens in Example 3 satisfiesconditional expressions (1) to (18).

FIG. 6 shows spherical aberration (mm), astigmatism (mm), and distortion(%) of the imaging lens in Example 3. As shown in FIG. 6, eachaberration is corrected properly.

Example 4

The basic lens data of Example 4 is shown below in Table 4.

TABLE 4 Numerical Data Example 4 Unit mm f = 4.26 Fno = 2.20 ω(°) = 39.0ih = 3.50 TTL = 5.00 Surface Data Surface Curvature Surface RefractiveAbbe Number i Radius r Distance d Index Nd Number νd (Object) InfinityInfinity  1 (Stop) Infinity −0.264  2* 1.692 0.610 1.5443 55.86  3*9.965 0.066  4* 9.192 0.240 1.6503 21.54  5* 3.580 0.295  6* 6.486 0.4581.5348 55.66  7* 11.687 0.322  8* −10.403 0.346 1.6391 23.25  9* 100.0000.209 10* 10.132 0.609 1.5348 55.66 11* −1.176 0.020 12* −12.263 0.5861.5348 55.66 13* 0.997 0.350 14 Infinity 0.210 1.5168 64.20 15 Infinity0.751 Image Plane Infinity Constituent Lens Data Lens Start SurfaceFocal Length 1 2 3.65 2 4 −9.17 3 6 26.44 4 8 −14.73 5 10 2.01 6 12−1.70 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5thSurface 6th Surface 7th Surface k 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 A4 −1.140E−02  −2.355E−01  −3.247E−01 −2.093E−01 −1.957E−01  −1.018E−01 A6 2.003E−02 4.400E−01 7.636E−01 5.165E−01 1.280E−01 −5.208E−02 A8 −8.841E−02  −4.256E−01  −7.201E−01 −5.112E−01 −1.771E−01   7.071E−02 A10 1.001E−01 1.269E−01 2.722E−01 2.929E−01 2.030E−01 −3.804E−02 A12 −5.931E−02  0.000E+00 −1.222E−02 −6.154E−02 −5.938E−02   2.315E−02 A14 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 A16 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 8th Surface 9th Surface 10th Surface11th Surface 12th Surface 13th Surface k 0.000E+00 0.000E+00 0.000E+00−7.797E+00 0.000E+00 −7.557E+00 A4 −6.768E−02  −1.478E−01  −2.750E−03  5.950E−02 −9.737E−02  −8.533E−02 A6 1.315E−02 1.509E−01 −1.134E−02 −7.888E−04 2.050E−02  4.115E−02 A8 −2.011E−02  −1.931E−01  −7.920E−03 −1.052E−02 1.037E−02 −1.547E−02 A10 −1.865E−03  1.782E−01 1.722E−03−2.255E−03 −5.002E−03   3.789E−03 A12 2.094E−02 −9.064E−02  0.000E+00 3.285E−03 7.700E−04 −5.726E−04 A14 −9.781E−03  2.344E−02 0.000E+00−8.406E−04 −4.159E−05   4.742E−05 A16 0.000E+00 −2.462E−03  0.000E+00 6.770E−05 0.000E+00 −1.621E−06 f12 = 5.32 E5 = 0.34 Ph51 = 0.95

As shown in Table 13, the imaging lens in Example 4 satisfiesconditional expressions (1) to (18).

FIG. 8 shows spherical aberration (mm), astigmatism (mm), and distortion(%) of the imaging lens in Example 4. As shown in FIG. 8, eachaberration is corrected properly.

Example 5

The basic lens data of Example 5 is shown below in Table 5.

TABLE 5 Numerical Data Example 5 Unit mm f = 3.83 Fno = 2.15 ω(°) = 39.0ih = 3.14 TTL = 4.43 Surface Data Surface Curvature Surface RefractiveAbbe Number i Radius r Distance d Index Nd Number νd (Object) InfinityInfinity  1 (Stop) Infinity −0.257  2* 1.470 0.573 1.5443 55.86  3*5.162 0.021  4* 5.042 0.223 1.6391 23.25  5* 2.593 0.245  6* 3.750 0.3611.5348 55.66  7* 5.160 0.252  8* 4.525 0.320 1.6391 23.25  9* 3.3970.310 10* 15.298 0.527 1.5348 55.66 11* −1.303 0.101 12* −13.470 0.5081.5348 55.66 13* 1.108 0.300 14 Infinity 0.210 1.5168 64.20 15 Infinity0.549 Image Plane Infinity Constituent Lens Data Lens Start SurfaceFocal Length 1 2 3.58 2 4 −8.66 3 6 23.55 4 8 −23.99 5 10 2.27 6 12−1.89 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5thSurface 6th Surface 7th Surface k −1.078E+00  3.320E−01 −8.751E+00−3.071E+01  0.000E+00  0.000E+00 A4 3.168E−02 −3.840E−01  −4.028E−01 8.816E−02 −1.367E−01 −1.311E−01 A6 4.980E−02 4.008E−01  5.842E−01−4.610E−02  2.134E−01  1.223E−01 A8 −1.736E−01  1.821E+00  1.888E+00 6.821E−01 −1.190E+00 −2.058E−01 A10 2.593E−01 −6.565E+00  −7.513E+00−1.707E+00  3.493E+00 −1.454E−01 A12 −1.941E−01  8.564E+00  1.062E+01 1.968E+00 −5.729E+00  7.387E−01 A14 1.686E−02 −5.202E+00  −7.009E+00−8.380E−01  4.823E+00 −8.386E−01 A16 0.000E+00 1.220E+00  1.818E+00 4.273E−02 −1.539E+00  3.527E−01 8th Surface 9th Surface 10th Surface11th Surface 12th Surface 13th Surface k 0.000E+00 0.000E+00  0.000E+00−8.035E+00  0.000E+00 −7.692E+00 A4 −2.588E−01  −2.643E−01   7.689E−02 1.087E−01 −9.204E−02 −1.091E−01 A6 2.378E−01 2.097E−01 −4.853E−02 6.958E−02 −2.832E−02  4.746E−02 A8 −1.892E−01  −1.820E−01  −2.715E−02−1.569E−01  4.708E−02 −1.720E−02 A10 3.666E−02 1.247E−01  1.353E−02 9.217E−02 −1.656E−02  3.834E−03 A12 3.159E−02 −3.977E−02  −2.325E−03−2.788E−02  2.504E−03 −4.601E−04 A14 −2.498E−02  9.051E−05  5.748E−04 4.564E−03 −1.433E−04  2.270E−05 A16 0.000E+00 1.596E−03 −7.488E−05−3.209E−04 −1.054E−07  0.000E+00 f12 = 5.27 E5 = 0.30 Ph51 = 0.98

As shown in Table 13, the imaging lens in Example 5 satisfiesconditional expressions (1) to (18).

FIG. 10 shows spherical aberration (mm), astigmatism (mm), anddistortion (%) of the imaging lens in Example 5. As shown in FIG. 10,each aberration is corrected properly.

Example 6

The basic lens data of Example 6 is shown below in Table 6.

TABLE 6 Numerical Data Example 6 Unit mm f = 3.83 Fno = 2.15 ω(°) = 39.0ih = 3.14 TTL = 4.43 Surface Data Surface Curvature Surface RefractiveAbbe Number i Radius r Distance d Index Nd Number νd (Object) InfinityInfinity  1 (Stop) Infinity −0.265  2* 1.444 0.580 1.5443 55.86  3*4.908 0.028  4* 5.747 0.223 1.6391 23.25  5* 2.904 0.253  6* 4.224 0.3601.5348 55.66  7* 5.604 0.283  8* 6.573 0.320 1.6391 23.25  9* 4.2320.248 10* 12.360 0.534 1.5348 55.66 11* −1.340 0.102 12* −15.883 0.5081.5348 55.66 13* 1.116 0.300 14 Infinity 0.210 1.5168 64.20 15 Infinity0.552 Image Plane Infinity Constituent Lens Data Lens Start SurfaceFocal Length 1 2 3.55 2 4 −9.47 3 6 29.39 4 8 −19.63 5 10 2.29 6 12−1.93 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5thSurface 6th Surface 7th Surface k −1.030E+00  0.000E+00 0.000E+00−2.500E+01   0.000E+00 0.000E+00 A4 3.317E−02 −3.693E−01  −4.006E−01 1.238E−02 −1.199E−01 −1.295E−01  A6 4.506E−02 8.164E−01 1.113E+003.578E−01 −7.253E−02 1.416E−01 A8 −1.365E−01  −9.819E−01  −1.381E+00 −4.760E−01   4.698E−01 −4.336E−01  A10 1.982E−01 3.965E−01 7.323E−013.644E−01 −1.070E+00 6.745E−01 A12 −1.452E−01  0.000E+00 −6.486E−02 −3.459E−02   1.054E+00 −6.075E−01  A14 0.000E+00 0.000E+00 0.000E+000.000E+00 −3.225E−01 2.478E−01 A16 0.000E+00 0.000E+00 0.000E+000.000E+00  0.000E+00 0.000E+00 8th Surface 9th Surface 10th Surface 11thSurface 12th Surface 13th Surface k 0.000E+00 0.000E+00 0.000E+00−9.688E+00   0.000E+00 −8.347E+00  A4 −1.908E−01  −2.130E−01  8.072E−029.241E−02 −8.973E−02 −8.920E−02  A6 1.087E−01 1.111E−01 −9.364E−02 7.874E−02 −2.778E−02 2.903E−02 A8 2.771E−02 −2.788E−02  8.791E−03−1.948E−01   4.702E−02 −7.062E−03  A10 −2.129E−01  −3.660E−02  1.013E−031.345E−01 −1.663E−02 1.007E−03 A12 1.886E−01 5.533E−02 0.000E+00−4.859E−02   2.509E−03 −7.062E−05  A14 −6.522E−02  −2.829E−02  0.000E+009.371E−03 −1.417E−04 1.763E−06 A16 0.000E+00 4.795E−03 0.000E+00−7.531E−04  −2.680E−07 0.000E+00 f12 = 4.99 E5 = 0.30 Ph51 = 0.92

As shown in Table 13, the imaging lens in Example 6 satisfiesconditional expressions (1) to (18).

FIG. 12 shows spherical aberration (mm), astigmatism (mm), anddistortion (%) of the imaging lens in Example 6. As shown in FIG. 12,each aberration is corrected properly.

Example 7

The basic lens data of Example 7 is shown below in Table 7.

TABLE 7 Numerical Data Example 7 Unit mm f = 3.84 Fno = 2.16 ω(°) = 39.0ih = 3.14 TTL = 4.43 Surface Data Surface Curvature Surface RefractiveAbbe Number i Radius r Distance d Index Nd Number νd (Object) InfinityInfinity  1 (Stop) Infinity −0.271  2* 1.437 0.591 1.5443 55.86  3*5.668 0.026  4* 6.528 0.223 1.6391 23.25  5* 2.922 0.265  6* 4.617 0.3531.5348 55.66  7* 5.829 0.278  8* 6.839 0.320 1.6391 23.25  9* 6.0740.268 10* −43.898 0.535 1.5348 55.66 11* −1.210 0.059 12* −17.664 0.5081.5348 55.66 13* 1.041 0.300 14 Infinity 0.210 1.5168 64.20 15 Infinity0.565 Image Plane Infinity Constituent Lens Data Lens Start SurfaceFocal Length 1 2 3.37 2 4 −8.48 3 6 37.69 4 8 −101.52 5 10 2.32 6 12−1.82 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5thSurface 6th Surface 7th Surface k −9.773E−01  0.000E+00 0.000E+00−2.500E+01  0.000E+00  0.000E+00 A4 3.518E−02 −3.660E−01  −3.850E−01 2.674E−02 −1.661E−01  −1.178E−01 A6 3.941E−02 8.299E−01 1.059E+002.690E−01 1.420E−01 −6.370E−02 A8 −1.363E−01  −9.798E−01  −1.209E+00 −1.997E−01  −2.435E−01   1.589E−01 A10 2.039E−01 3.843E−01 5.213E−012.175E−02 2.078E−01 −2.506E−01 A12 −1.466E−01  0.000E+00 1.708E−021.112E−01 0.000E+00  1.634E−01 A14 0.000E+00 0.000E+00 0.000E+000.000E+00 0.000E+00  0.000E+00 A16 0.000E+00 0.000E+00 0.000E+000.000E+00 0.000E+00  0.000E+00 8th Surface 9th Surface 10th Surface 11thSurface 12th Surface 13th Surface k 6.530E−06 0.000E+00 0.000E+00−8.613E+00  0.000E+00 −8.102E+00 A4 −7.490E−02  −8.154E−02  8.974E−026.549E−02 −8.688E−02  −8.975E−02 A6 −2.533E−01  −1.514E−01  −1.013E−01 8.292E−02 −2.917E−02   2.903E−02 A8 6.735E−01 3.608E−01 4.820E−03−1.933E−01  4.679E−02 −6.732E−03 A10 −9.884E−01  −4.596E−01  4.231E−031.345E−01 −1.659E−02   9.187E−04 A12 6.864E−01 3.307E−01 0.000E+00−4.861E−02  2.523E−03 −6.836E−05 A14 −1.864E−01  −1.209E−01  0.000E+009.361E−03 −1.415E−04   2.511E−06 A16 0.000E+00 1.717E−02 0.000E+00−7.565E−04  −7.668E−07  −3.133E−08 f12 = 4.86 E5 = 0.30 Ph51 = 0.74

As shown in Table 13, the imaging lens in Example 7 satisfiesconditional expressions (1) to (18).

FIG. 14 shows spherical aberration (mm), astigmatism (mm), anddistortion (%) of the imaging lens in Example 7. As shown in FIG. 14,each aberration is corrected properly.

Example 8

The basic lens data of Example 8 is shown below in Table 8.

TABLE 8 Numerical Data Example 8 Unit mm f = 3.89 Fno = 2.24 ω(°) = 38.6ih = 3.14 TTL = 4.43 Surface Data Surface Curvature Surface RefractiveAbbe Number i Radius r Distance d Index Nd Number νd (Object) InfinityInfinity  1 (Stop) Infinity −0.266  2* 1.426 0.587 1.5443 55.86  3*5.934 0.036  4* 7.067 0.223 1.6391 23.25  5* 3.009 0.273  6* 5.729 0.3541.5348 55.66  7* 8.689 0.282  8* 16.553 0.320 1.6391 23.25  9* 10.0220.263 10* 18.021 0.505 1.5348 55.66 11* −1.336 0.055 12* −9.729 0.5081.5348 55.66 13* 1.099 0.300 14 Infinity 0.210 1.5168 64.20 15 Infinity0.585 Image Plane Infinity Constituent Lens Data Lens Start SurfaceFocal Length 1 2 3.30 2 4 −8.38 3 6 30.18 4 8 −40.52 5 10 2.35 6 12−1.82 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5thSurface 6th Surface 7th Surface k −9.949E−01  0.000E+00 0.000E+00−1.424E+01  0.000E+00  0.000E+00 A4 3.632E−02 −3.296E−01  −3.707E−01 −5.621E−02  −1.637E−01  −9.995E−02 A6 4.791E−02 7.065E−01 9.815E−014.590E−01 1.183E−01 −1.041E−01 A8 −1.651E−01  −8.135E−01  −1.067E+00 −4.713E−01  −1.748E−01   2.300E−01 A10 2.595E−01 2.980E−01 3.925E−012.565E−01 1.731E−01 −2.959E−01 A12 −1.832E−01  0.000E+00 5.971E−022.688E−02 −3.747E−05   1.764E−01 A14 0.000E+00 0.000E+00 0.000E+000.000E+00 0.000E+00  0.000E+00 A16 0.000E+00 0.000E+00 0.000E+000.000E+00 0.000E+00  0.000E+00 8th Surface 9th Surface 10th Surface 11thSurface 12th Surface 13th Surface k 0.000E+00 0.000E+00 0.000E+00−9.015E+00  0.000E+00 −8.353E+00 A4 −7.894E−02  −1.144E−01  5.526E−021.327E−01 −1.128E−01  −1.186E−01 A6 −1.053E−01  −1.465E−02  −8.701E−02 −5.089E−02  2.299E−02  6.874E−02 A8 3.001E−01 1.013E−01 3.153E−04−4.242E−02  1.862E−02 −3.235E−02 A10 −4.832E−01  −1.381E−01  5.016E−033.217E−02 −9.583E−03   1.007E−02 A12 3.357E−01 9.738E−02 8.967E−05−7.607E−03  1.708E−03 −1.930E−03 A14 −8.881E−02  −3.325E−02  0.000E+005.869E−04 −1.103E−04   2.029E−04 A16 0.000E+00 4.218E−03 0.000E+005.270E−06 −9.641E−08  −8.825E−06 f12 = 4.73 E5 = 0.29 Ph51 = 0.79

As shown in Table 13, the imaging lens in Example 8 satisfiesconditional expressions (1) to (18).

FIG. 16 shows spherical aberration (mm), astigmatism (mm), anddistortion (%) of the imaging lens in Example 8. As shown in FIG. 16,each aberration is corrected properly.

Example 9

The basic lens data of Example 9 is shown below in Table 9.

TABLE 9 Numerical Data Example 9 Unit mm f = 3.86 Fno = 2.20 ω(°) = 38.8ih = 3.14 TTL = 4.43 Surface Data Surface Curvature Surface RefractiveAbbe Number i Radius r Distance d Index Nd Number νd (Object) InfinityInfinity  1 (Stop) Infinity −0.270  2* 1.418 0.605 1.5443 55.86  3*6.949 0.032  4* 9.339 0.223 1.6391 23.25  5* 3.376 0.307  6* 8.309 0.3601.5348 55.66  7* 21.223 0.335  8* −5.882 0.320 1.6391 23.25  9* −14.7110.119 10* 11.304 0.523 1.5348 55.66 11* −1.329 0.062 12* −12.951 0.5081.5348 55.66 13* 1.060 0.300 14 Infinity 0.210 1.5168 64.20 15 Infinity0.596 Image Plane Infinity Constituent Lens Data Lens Start SurfaceFocal Length 1 2 3.15 2 4 −8.40 3 6 25.29 4 8 −15.56 5 10 2.26 6 12−1.81 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5thSurface 6th Surface 7th Surface k −9.531E−01  0.000E+00 0.000E+000.000E+00 0.000E+00  0.000E+00 A4 3.395E−02 −3.642E−01  −3.934E−01 −1.082E−01  −1.828E−01  −1.166E−01 A6 6.286E−02 8.690E−01 1.136E+005.019E−01 6.653E−02 −1.224E−01 A8 −2.029E−01  −1.054E+00  −1.318E+00 −5.123E−01  −8.182E−02   2.065E−01 A10 3.160E−01 4.108E−01 5.291E−012.587E−01 7.324E−02 −2.230E−01 A12 −2.175E−01  0.000E+00 5.611E−026.857E−02 6.212E−02  1.464E−01 A14 0.000E+00 0.000E+00 0.000E+000.000E+00 0.000E+00  0.000E+00 A16 0.000E+00 0.000E+00 0.000E+000.000E+00 0.000E+00  0.000E+00 8th Surface 9th Surface 10th Surface 11thSurface 12th Surface 13th Surface k 0.000E+00 0.000E+00 0.000E+00−9.435E+00  0.000E+00 −7.741E+00 A4 −5.136E−02  −1.435E−01  −5.240E−03 8.597E−02 −1.465E−01  −1.203E−01 A6 −5.208E−02  1.393E−01 −1.902E−02 −1.548E−02  3.878E−02  6.928E−02 A8 4.408E−02 −2.507E−01  −2.170E−02 −1.697E−02  2.208E−02 −3.218E−02 A10 −1.320E−01  2.880E−01 7.136E−03−6.481E−03  −1.329E−02   9.897E−03 A12 1.448E−01 −1.715E−01  0.000E+001.079E−02 2.515E−03 −1.866E−03 A14 −4.854E−02  5.253E−02 0.000E+00−3.443E−03  −1.661E−04   1.920E−04 A16 0.000E+00 −6.757E−03  0.000E+003.457E−04 −1.454E−07  −8.138E−06 f12 = 4.43 E5 = 0.29 Ph51 = 0.79

As shown in Table 13, the imaging lens in Example 9 satisfiesconditional expressions (1) to (18).

FIG. 18 shows spherical aberration (mm), astigmatism (mm), anddistortion (%) of the imaging lens in Example 9. As shown in FIG. 18,each aberration is corrected properly.

Example 10

The basic lens data of Example 10 is shown below in Table 10.

TABLE 10 Numerical Data Example 10 Unit mm f = 3.87 Fno = 2.25 ω(°) =38.7 ih = 3.14 TTL = 4.427 Surface Data Surface Curvature SurfaceRefractive Abbe Number i Radius r Distance d Index Nd Number νd (Object)Infinity Infinity  1 (Stop) Infinity −0.255  2* 1.449 0.561 1.5443 55.86 3* 6.921 0.052  4* 5.940 0.223 1.6391 23.25  5* 2.447 0.238  6* 4.0640.360 1.5348 55.66  7* 9.057 0.348  8* −55.532 0.320 1.6391 23.25  9*16.329 0.208 10* 16.659 0.488 1.5348 55.66 11* −1.458 0.050 12* −27.4610.550 1.5348 55.66 13* 1.119 0.300 14 Infinity 0.210 1.5168 64.20 15Infinity 0.590 Image Plane Infinity Constituent Lens Data Lens StartSurface Focal Length 1 2 3.25 2 4 −6.68 3 6 13.45 4 8 −19.71 5 10 2.53 612 −2.00 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5thSurface 6th Surface 7th Surface k 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 A4 −8.459E−03  −3.124E−01  −4.540E−01 −2.715E−01 −2.231E−01  −1.256E−01 A6 3.763E−02 8.122E−01 1.359E+00 8.932E−01 2.687E−01 −2.083E−02 A8 −1.617E−01  −9.870E−01  −1.700E+00 −1.136E+00 −3.925E−01   9.294E−02 A10 2.492E−01 3.793E−01 8.318E−01 8.266E−01 5.290E−01 −8.488E−02 A12 −1.719E−01  0.000E+00 −5.708E−02 −2.327E−01 −2.335E−01   7.342E−02 A14 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 A16 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 8th Surface 9th Surface 10th Surface11th Surface 12th Surface 13th Surface k 0.000E+00 0.000E+00 0.000E+00−1.001E+01 0.000E+00 −7.644E+00 A4 −1.079E−01  −1.919E−01  7.893E−03 9.096E−02 −1.493E−01  −1.185E−01 A6 −5.051E−02  1.824E−01 −2.672E−02 −1.761E−02 3.817E−02  6.793E−02 A8 1.834E−01 −2.823E−01  −2.118E−02 −1.664E−02 2.212E−02 −3.208E−02 A10 −3.154E−01  3.285E−01 7.638E−03−6.499E−03 −1.328E−02   9.915E−03 A12 2.542E−01 −2.089E−01  0.000E+00 1.074E−02 2.522E−03 −1.866E−03 A14 −8.380E−02  6.761E−02 0.000E+00−3.436E−03 −1.659E−04   1.920E−04 A16 0.000E+00 −8.947E−03  0.000E+00 3.479E−04 −4.711E−07  −8.201E−06 f12 = 5.22 E5 = 0.29 Ph51 = 0.76

As shown in Table 13, the imaging lens in Example 10 satisfiesconditional expressions (1) to (18).

FIG. 20 shows spherical aberration (mm), astigmatism (mm), anddistortion (%) of the imaging lens in Example 10. As shown in FIG. 20,each aberration is corrected properly.

Example 11

The basic lens data of Example 11 is shown below in Table 11.

TABLE 11 Numerical Data Example 11 Unit mm f = 3.87 Fno = 2.24 ω(°) =38.7 ih = 3.14 TTL = 4.43 Surface Data Surface Curvature SurfaceRefractive Abbe Number i Radius r Distance d Index Nd Number νd (Object)Infinity Infinity  1 (Stop) Infinity −0.255  2* 1.452 0.558 1.5443 55.86 3* 6.829 0.054  4* 5.661 0.223 1.6391 23.25  5* 2.388 0.237  6* 4.0040.363 1.5348 55.66  7* 9.272 0.356  8* −25.515 0.320 1.6391 23.25  9*26.636 0.193 10* 27.731 0.474 1.5348 55.66 11* −1.446 0.050 12* −415.4250.551 1.5348 55.66 13* 1.094 0.300 14 Infinity 0.210 1.5168 64.20 15Infinity 0.611 Image Plane Infinity Constituent Lens Data Lens StartSurface Focal Length 1 2 3.27 2 4 −6.64 3 6 12.87 4 8 −20.34 5 10 2.58 612 −2.04 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5thSurface 6th Surface 7th Surface k 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 A4 −8.839E−03  −3.026E−01  −4.602E−01 −2.854E−01 −2.248E−01  −1.231E−01 A6 4.225E−02 7.503E−01 1.325E+00 8.818E−01 2.401E−01 −3.201E−02 A8 −1.754E−01  −8.651E−01  −1.595E+00 −1.042E+00 −3.280E−01   8.319E−02 A10 2.666E−01 3.090E−01 7.499E−01 6.962E−01 4.804E−01 −4.154E−02 A12 −1.775E−01  0.000E+00 −4.687E−02 −1.749E−01 −2.219E−01   4.578E−02 A14 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 A16 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 8th Surface 9th Surface 10th Surface11th Surface 12th Surface 13th Surface k 0.000E+00 0.000E+00 0.000E+00−9.882E+00 0.000E+00 −7.391E+00 A4 −9.911E−02  −1.954E−01  9.741E−03 9.921E−02 −1.497E−01  −1.191E−01 A6 −3.002E−02  2.214E−01 −2.372E−02 −1.971E−02 3.789E−02  6.798E−02 A8 1.033E−01 −3.637E−01  −2.076E−02 −1.598E−02 2.203E−02 −3.212E−02 A10 −2.049E−01  4.193E−01 7.222E−03−6.482E−03 −1.329E−02   9.925E−03 A12 1.905E−01 −2.617E−01  0.000E+00 1.069E−02 2.526E−03 −1.867E−03 A14 −6.974E−02  8.264E−02 0.000E+00−3.455E−03 −1.656E−04   1.922E−04 A16 0.000E+00 −1.056E−02  0.000E+00 3.528E−04 −3.921E−07  −8.205E−06 f12 = 5.28 E5 = 0.29 Ph51 = 0.72

As shown in Table 13, the imaging lens in Example 11 satisfiesconditional expressions (1) to (18).

FIG. 22 shows spherical aberration (mm), astigmatism (mm), anddistortion (%) of the imaging lens in Example 11. As shown in FIG. 22,each aberration is corrected properly.

Example 12

The basic lens data of Example 12 is shown below in Table 12.

TABLE 12 Numerical Data Example 12 Unit mm f = 3.87 Fno = 2.25 ω(°) =38.7 ih = 3.14 TTL = 4.43 Surface Data Surface Curvature SurfaceRefractive Abbe Number i Radius r Distance d Index Nd Number νd (Object)Infinity Infinity  1 (Stop) Infinity −0.255  2* 1.447 0.557 1.5443 55.86 3* 6.293 0.055  4* 5.636 0.223 1.6391 23.25  5* 2.454 0.241  6* 4.0450.362 1.5348 55.66  7* 9.717 0.355  8* −16.823 0.320 1.6391 23.25  9*25.711 0.184 10* 13.452 0.489 1.5348 55.66 11* −1.432 0.050 12* −30.9400.550 1.5348 55.66 13* 1.100 0.300 14 Infinity 0.210 1.5168 64.20 15Infinity 0.606 Image Plane Infinity Constituent Lens Data Lens StartSurface Focal Length 1 2 3.32 2 4 −6.99 3 6 12.68 4 8 −15.87 5 10 2.45 612 −1.97 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5thSurface 6th Surface 7th Surface k 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 A4 −8.750E−03  −3.062E−01  −4.555E−01 −2.798E−01 −2.211E−01  −1.092E−01 A6 4.605E−02 7.417E−01 1.293E+00 8.894E−01 2.468E−01 −5.980E−02 A8 −1.878E−01  −8.623E−01  −1.558E+00 −1.101E+00 −3.714E−01   1.321E−01 A10 2.840E−01 3.140E−01 7.430E−01 7.882E−01 5.053E−01 −1.046E−01 A12 −1.884E−01  0.000E+00 −4.688E−02 −2.102E−01 −2.183E−01   7.224E−02 A14 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 A16 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00  0.000E+00 8th Surface 9th Surface 10th Surface11th Surface 12th Surface 13th Surface k 0.000E+00 0.000E+00 0.000E+00−1.044E+01 0.000E+00 −7.726E+00 A4 −9.725E−02  −2.071E−01  2.380E−03 9.630E−02 −1.463E−01  −1.178E−01 A6 3.995E−03 2.604E−01 −2.466E−02 −2.211E−02 3.796E−02  6.783E−02 A8 4.139E−02 −4.239E−01  −2.134E−02 −1.530E−02 2.201E−02 −3.208E−02 A10 −1.370E−01  4.792E−01 7.539E−03−6.348E−03 −1.330E−02   9.922E−03 A12 1.425E−01 −3.007E−01  0.000E+00 1.069E−02 2.525E−03 −1.867E−03 A14 −5.615E−02  9.644E−02 0.000E+00−3.459E−03 −1.657E−04   1.919E−04 A16 0.000E+00 −1.250E−02  0.000E+00 3.517E−04 −2.983E−07  −8.158E−06 f12 = 5.24 E5 = 0.29 Ph51 = 0.77

As shown in Table 13, the imaging lens in Example 12 satisfiesconditional expressions (1) to (18).

FIG. 24 shows spherical aberration (mm), astigmatism (mm), anddistortion (%) of the imaging lens in Example 12. As shown in FIG. 24,each aberration is corrected properly.

As explained above, the imaging lens according to this embodiment of thepresent invention achieves low-profileness with a total track length TTLof less than 5 mm, a ratio of total track length TTL to twice themaximum image height ih (TTL/2ih) of about 0.7, and offers highbrightness with an F-value of 2.3 or less and a wide field of view ofabout 80 degrees. Thus, the present invention provides a compacthigh-resolution imaging lens which satisfies the demand forlow-profileness, meets the demands for a low F-value and a wide field ofview in a balanced manner, and corrects various aberrations properly,though it is composed of six constituent lenses.

Table 13 shows data on Examples 1 to 12 in relation to the conditionalexpressions (1) to (18).

TABLE 13 Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam-Exam- Exam- ple 1 ple 2 ple 3 ple 4 ple 5 ple 6 ple 7 ple 8 ple 9 ple 10ple 11 ple 12 Conditional 0.26 0.26 0.24 0.24 0.27 0.27 0.26 0.27 0.250.26 0.26 0.26 Expression (1) AG16/Σd Conditional 32.4 32.4 32.4 32.432.4 32.4 32.4 32.4 32.4 32.4 32.4 32.4 Expression (2) νd3 − νd4Conditional 0.25 0.26 0.27 0.27 0.31 0.29 0.24 0.25 0.25 0.24 0.23 0.25Expression (3) Ph51/ih Conditional 1.11 1.07 0.87 0.87 1.09 1.10 1.081.07 1.05 1.17 1.19 1.14 Expression (4) (f5 + |f6|)/f Conditional 0.870.90 0.90 0.86 0.94 0.93 0.88 0.85 0.82 0.84 0.84 0.86 Expression (5)f1/f Conditional 2.67 2.97 3.29 2.28 3.12 3.04 2.62 2.48 2.13 2.40 2.462.54 Expression (6) (r3 + r4)/(r3 − r4) Conditional YES YES YES YES YESYES YES YES YES YES YES YES Expression (7) P4 < P2 < P6 P2 = (|1/f2|)0.14 0.10 0.10 0.11 0.12 0.11 0.12 0.12 0.12 0.15 0.15 0.14 P4 =(|1/f4|) 0.07 0.06 0.09 0.07 0.04 0.05 0.01 0.02 0.06 0.05 0.05 0.06 P6= (|1/f6|) 0.52 0.49 0.58 0.59 0.53 0.52 0.55 0.55 0.55 0.50 0.49 0.51Conditional YES YES YES YES YES YES YES YES YES YES YES YES Expression(8) P3 < P1 < P5 P1 = (1/f1) 0.30 0.26 0.26 0.27 0.28 0.28 0.30 0.300.32 0.31 0.31 0.30 P3 = (1/f3) 0.08 0.07 0.05 0.04 0.04 0.03 0.03 0.030.04 0.07 0.08 0.08 P5 = (1/f5) 0.42 0.39 0.50 0.50 0.44 0.44 0.43 0.430.44 0.40 0.39 0.41 Conditional 32.6 34.3 34.3 34.3 32.6 32.6 32.6 32.632.6 32.6 32.6 32.6 Expression (9) νd1 − νd2 Conditional 55.7 55.7 55.755.7 55.7 55.7 55.7 55.7 55.7 55.7 55.7 55.7 Expression (10) νd5Conditional 55.7 55.7 55.7 55.7 55.7 55.7 55.7 55.7 55.7 55.7 55.7 55.7Expression (11) νd6 Conditional 0.91 0.95 1.12 1.04 1.04 1.05 1.05 0.991.03 0.89 0.86 0.89 Expression (12) D5/D6 Conditional 1.30 2.04 0.470.47 2.65 2.66 1.54 1.40 1.60 1.29 1.29 1.29 Expression (13) (T5/f)*100Conditional 2.32 1.60 1.28 2.44 1.18 1.72 1.78 4.25 1.53 14.34 6.59 4.35Expression (14) |r7|/f Conditional 0.59 0.58 0.54 0.56 0.58 0.55 0.560.58 0.55 0.60 0.62 0.60 Expression (15) E5/D5 Conditional 1.34 1.301.27 1.25 1.38 1.30 1.27 1.22 1.15 1.35 1.36 1.35 Expression (16) f12/fConditional 0.81 0.82 0.82 0.82 0.82 0.82 0.82 0.81 0.82 0.81 0.81 0.81Expression (17) ih/f Conditional 0.70 0.71 0.71 0.71 0.70 0.70 0.70 0.700.70 0.70 0.70 0.70 Expression (18) TTL/2ih

When the imaging lens composed of six constituent lenses according tothe present invention is used in an image pickup device mounted in anincreasingly compact and low-profile smartphone or mobile terminal, gameconsole, information terminal such as a PC or robot, home appliance orvehicle with a camera function, it contributes to making the cameralow-profile and offering a wide field of view, and enhances the cameraperformance.

1. An imaging lens which forms an image of an object on a solid-stateimage sensor, comprising, in order from an object side to an image side:a first lens with positive refractive power having a convex surface onthe object side; a second lens with negative refractive power as ameniscus lens having a concave surface on the image side; a third lenshaving a concave surface on the image side; a fourth lens; a fifth lenswith positive refractive power having a convex surface on the imageside; and a sixth lens with negative refractive power having a concavesurface on each of the object side and the image side.
 2. The imaginglens according to claim 1, wherein an aperture stop is located on theobject side of the first lens.
 3. The imaging lens according to claim 1,comprising: a lens group with positive composite refractive powerincluding the first lens, the second lens, and the third lens; and alens group with negative composite refractive power including the fourthlens, the fifth lens, and the sixth lens.
 4. The imaging lens accordingto claim 1, wherein a conditional expression (1) below is satisfied:0.18<AG16/Σd<0.3  (1) where AG16: sum of air gaps on an optical axisfrom the first lens to the sixth lens Σd: distance on the optical axisfrom the object-side surface of the first lens to the image-side surfaceof the sixth lens.
 5. The imaging lens according to claim 1, wherein aconditional expression (2) below is satisfied:20<vd3−vd4<40  (2) where vd3: Abbe number of the third lens at d-rayvd4: Abbe number of the fourth lens at d-ray.
 6. The imaging lensaccording to claim 1, wherein the fifth lens has an aspheric surfacewith a pole point off an optical axis on the object-side surfacethereof.
 7. The imaging lens according to claim 6, wherein a conditionalexpression (3) below is satisfied:0.2<Ph51/ih<0.9  (3) where Ph51: vertical height of the pole point onthe object-side surface of the fifth lens from the optical axis ih:maximum image height.
 8. The imaging lens according to claim 1, whereina conditional expression (4) below is satisfied:(f5+|f6|)/f<1.3  (4) where f: focal length of an overall optical systemof the imaging lens f5: focal length of the fifth lens f6: focal lengthof the sixth lens.
 9. The imaging lens according to claim 1, wherein aconditional expression (5) below is satisfied:0.5<f1/f<1.5  (5) where f: focal length of an overall optical system ofthe imaging lens f1: focal length of the first lens.
 10. The imaginglens according to claim 1, wherein a conditional expression (6) below issatisfied:1.5<(r3+r4)/(r3−r4)<4.5  (6) where r3: curvature radius of theobject-side surface of the second lens r4: curvature radius of theimage-side surface of the second lens.
 11. The imaging lens according toclaim 1, wherein the third lens has positive refractive power and thefourth lens has a concave surface on the object side and has negativerefractive power.
 12. The imaging lens according to claim 11, whereinthe second lens, the fourth lens, and the sixth lens have negativerefractive power and satisfy a conditional expression (7) below:P4<P2<P6  (7) where P2: refractive power of the second lens P4:refractive power of the fourth lens P6: refractive power of the sixthlens.
 13. The imaging lens according to claim 11, wherein the firstlens, the third lens, and the fifth lens have positive refractive powerand satisfy a conditional expression (8) below:P3<P1<P5  (8) where P1: refractive power of the first lens P3:refractive power of the third lens P5: refractive power of the fifthlens.
 14. The imaging lens according to claim 1, wherein the sixth lenshas an aspheric surface with a pole point off an optical axis on theimage-side surface thereof.
 15. The imaging lens according to claim 1,wherein a conditional expression (9) below is satisfied:20<vd1−vd2<40  (9) where vd1: Abbe number of the first lens at d-rayvd2: Abbe number of the second lens at d-ray.
 16. The imaging lensaccording to claim 15, wherein conditional expressions (10) and (11)below are satisfied:50<vd5<70  (10)50<vd6<70  (11) where vd5: Abbe number of the fifth lens at d-ray vd6:Abbe number of the sixth lens at d-ray.
 17. The imaging lens accordingto claim 1, wherein a conditional expression (12) below is satisfied:0.75<D5/D6<1.50  (12) where D5: thickness of the fifth lens on anoptical axis D6: thickness of the sixth lens on the optical axis. 18.The imaging lens according to claim 17, wherein a conditional expression(13) below is satisfied:0.35<(T5/f)×100<3.00  (13) where T5: distance on the optical axis fromthe image-side surface of the fifth lens to the object-side surface ofthe sixth lens f: focal length of an overall optical system of theimaging lens.
 19. The imaging lens according to claim 1, wherein aconditional expression (14) below is satisfied:0.6<|r7|/f<17.0  (14) where f: focal length of an overall optical systemof the imaging lens r7: curvature radius of the object-side surface ofthe fourth lens.
 20. The imaging lens according to claim 1, wherein aconditional expression (15) below is satisfied:0.45<E5/D5<1.20  (15) where E5: edge thickness of the fifth lens in amaximum effective diameter D5: thickness of the fifth lens on an opticalaxis.
 21. The imaging lens according to claim 1, wherein a conditionalexpression (16) below is satisfied:0.6<f12/f<2.0  (16) where f: focal length of an overall optical systemof the imaging lens f12: composite focal length of the first lens andthe second lens.
 22. The imaging lens according to claim 1, wherein aconditional expression (17) below is satisfied:0.80<ih/f<1.0  (17) where f: focal length of an overall optical systemof the imaging lens ih: maximum image height.
 23. The imaging lensaccording to claim 1, wherein a conditional expression (18) below issatisfied:TTL/2ih<1.0  (18) where TTL: total track length ih: maximum imageheight.